Unable to access GPIO running Home Assistant in Docker on Raspberry Pi

Configuration
1

Hi,

I am currently running Home Assistant in Docker using an image from https://hub.docker.com/r/homeassistant/home-assistant/ (v0.68.1) on a Raspberry Pi 3.

I have connected a DHT22 temperature and humidity sensor to the GPIO’s of the RasPi, but can’t get Home Assistant to read values from it. In my configuration.yaml I have added the following entry:

sensor:
  - platform: yr
  - platform: dht
    sensor: DHT22
    pin: 4
    monitored_conditions:
      - temperature
      - humidity

The error log of home assistant tells me, that there is an error accessing GPIO.

dht: Error on device update!

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/homeassistant/helpers/entity_platform.py", line 244, in _async_add_entity
    await entity.async_device_update(warning=False)
  File "/usr/lib/python3.6/site-packages/homeassistant/helpers/entity.py", line 327, in async_device_update
    yield from self.hass.async_add_job(self.update)
  File "/usr/lib/python3.6/concurrent/futures/thread.py", line 56, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/lib/python3.6/site-packages/homeassistant/components/sensor/dht.py", line 125, in update
    self.dht_client.update()
  File "/usr/lib/python3.6/site-packages/homeassistant/util/__init__.py", line 319, in wrapper
    result = method(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/homeassistant/components/sensor/dht.py", line 160, in update
    self.sensor, self.pin)
  File "/usr/lib/python3.6/site-packages/Adafruit_DHT/common.py", line 94, in read_retry
    humidity, temperature = read(sensor, pin, platform)
  File "/usr/lib/python3.6/site-packages/Adafruit_DHT/common.py", line 81, in read
    return platform.read(sensor, pin)
  File "/usr/lib/python3.6/site-packages/Adafruit_DHT/Raspberry_Pi_2.py", line 34, in read
    raise RuntimeError('Error accessing GPIO.')
RuntimeError: Error accessing GPIO.

On a normal Raspbian install this error usually occurs due to the user running home assistant not being in the GPIO group. The GPIO group in turn has access to /dev/gpiomem, which is needed to access the GPIO pins.

I tried giving access to the Docker container running home assistant by giving it access to /dev/gpiomem and by running it in privileged mode. by adding the following entries to my docker-compose.yaml.

..
volumes:
  ..
  - /dev/mem:/dev/mem
..
privileged: true
..

Neither of them resolved my problem.

Any idea to debug this problem would be appreciated.
Kind regards

2

That’s not the same as /dev/gpiomem is it?

I thought it was /sys/class/gpio

1 Like
3

Thank you! Your comment lead me to doublecheck my config again.

I had appened privileged: true option to the wrong container. Adding this option allowed me to access the gpio pins without adding any volumes.

/dev/mem was another suggestion I found over the internet. Without using privileged: true no combination of mounting /dev/mem, /dev/gpiomem nor sys/class/gpio solved the problem for me.

1 Like
4

How did you run this image https://hub.docker.com/r/homeassistant/home-assistant/ (v0.68.1) on a Raspberry Pi 3?
I’m trying run it, but i received the error message:
pi@raspberrypi:~/homeassistant $ docker-compose up
home-assistant is up-to-date
Attaching to home-assistant
home-assistant | standard_init_linux.go:190: exec user process caused “exec format error”

Could you help me?

Thanks

5

You can’t run that image. You need the image for the Raspberry Pi 3. The one you are trying to run is for x86_64 architecture